Blood pump with splitter impeller blades and splitter stator vanes and related methods

Abstract

A rotordynamic pump for delivering continuous flow of fluids, such as blood, is provided. In one embodiment, the pump includes a stator housing having an inlet and an outlet. A rotor hub is disposed within the stator housing having a mixed-stage or mixed-flow impeller. The mixed flow impeller includes both principle blades and splitter blades, the splitter blades exhibiting a shorter axial length than the principle blades. One or more stator vanes and extend radially inwardly from the stator housing. The splitter blades and principle blades are arranged in a circumferentially alternating pattern. The stator vanes include principle stator vanes and splitter stator vanes, the splitter stator vanes exhibiting a shorter axial length than the principle stator vanes. The splitter vanes and principle vanes are arranged in a circumferentially alternating pattern. The rotor hub may be magnetically suspended and rotated within the stator housing.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Patent Application No. 61 / 394,220, filed Oct. 18, 2010, and entitled BLOOD PUMP WITH SPLITTER IMPELLER BLADES AND SPLITTER STATOR BLADES. This application also claims priority to U.S. Provisional Patent Application No. 61 / 394,213 filed Oct. 18, 2010, entitled BLOOD PUMP WITH SEPARATE MIXED-FLOW AND AXIAL FLOW IMPELLER STAGES. The disclosures of the above referenced priority applications are incorporated by reference herein in their entireties.TECHNICAL FIELD[0002]This invention relates generally to pumps. More specifically, this invention relates to blood pumps, such as cardiac assist pumps that may be implanted in a patient.BACKGROUND OF THE INVENTION[0003]Rotordynamic pumps, such as centrifugal, mixed-flow, and axial-flow pumps with mechanical bearings or magnetically suspended systems, have been widely used as ventricular assist devices to support patients with heart diseases. In mag...

AI Technical Summary

Benefits of technology

[0021]High efficiency, low blood damage, and smooth operation at design and off-design conditions are the critical requirements for a long term implantable blood pump. High efficiency is accomplished with the inclusion of splitter blades for both impeller and stator. The leading edges of both the impeller and stator shorter splitter blades are staggered with respect to principle blades, and initiate subsequently to the leading edge of the principle blades and overlap a portion of the principle blades wherein both principle and splitter blades preferably terminate at the same position in meridional section. Such an arrangement lessens the flow blockage at the impeller inlet side, thus improving the uniformity of flow field at the impeller inlet region by preventing undesirable flow patterns such as the pre-rotation, retrograde flow, and inlet circulation from occurrence at the design and off-design conditions. Because splitter blades take some percentage of pressure loading from the principle blades, it makes the pressure distribution more uniform along the entire blade region and especially on the outlet side of the impeller blades and stator blades at all operating conditions. Therefore, the flow at the outlets of the impeller...

Problems solved by technology

One adverse outcome of operating a rotor at high rotational speeds is a tendency for high turbulence flow characteristics within the blood (e.g., high shear stress) that increase the extent and rate of red blood cell damage.

This is a challenge in developing a long-term implantable ventricular assist device.

Additionally, for centrifugal or mixed-flow blood pumps with shrouded impellers (i.e., a circumferentially revolved surface interconnecting the impeller blade tips), the fluid within the clearance space between a rotating front shroud and the stationary housing can demonstrate a complex three-dimensional structure, leading to retrograde leakage flow and strong disk friction loss.

The combination of disk friction loss and the strong vortical flow not only lowers pump efficiency but also potentially induces hemolysis and thrombosis.

For centrifugal or mixed-flow blood pumps with unshrouded or semi-open impellers, the lack of a front shroud introduces a problem due to the blade tip leakage flow from pressure-side to suction-side of the blades which occurs through the clearance between th...

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